Spring action terminal with locked barrel

ABSTRACT

A spring action terminal for connection to spark plugs made from a single piece of material, which has a locked barrel provided by a detent which also engages the spark plug.

United States Patent [1 1 Cronce Nov. 6, 1973 SPRING ACTION TERMINALWITH LOCKED BARREL [75] Inventor: Grant Woodrow Cronce, Port,

Huron, Mich.

[731 Assignee: Eltra Corporation, Toledo, Ohio [22] Filed: Oct. 28, 1971[21] Appl. No.: 193,247

[52] U.S. Cl 339/256 C [51] Int. Cl H0lr 11/22 [58] Field of Search339/213 S, 217 SP,

339/220 A, 218 S, 223 S, 258 C, 256 C, 26, 143 S, 47 S, 136 C [56]References Cited UNITED STATES PATENTS 3,546,665 12/1970 Zak ..339/256C3,223,963 12/1965 Rarey 339/223 S X 3,464,368 10/1968 Roberts et al.339/223 S 2,553,083 5/1951 Elliott 339/256 C FOREIGN PATENTS ORAPPLICATIONS 952,423 3/1964 Great Britain 339/258 C ry Ex min r-Ma in Armp Assistant Exaininer-William F. Pate, 111 Attorney-D. HenryStoltenberg [5 7 ABSTRACT A spring action terminal for connection tospark plugs made from a single piece of material, which has a lockedbarrel provided by a detent which also engages the spark plug.

2 Claims, 4 Drawing Figures PATENTEUNUV 6 I975 INVENTOR.

' GRANT W. CRONCE- .H ATTORNEY j SPRING ACTION TERMINAL WITI-I LOCKEDBARREL BACKGROUND OF THE INVENTION With the trend in manufacturingmoving toward greater automation, the search for simple, effectiveterminals has been augmented, particularly terminals for use withignition equipment in the automotive field. The terminal structure mustbe such that it can be manufactured in connected form with automaticallyoperated equipment on a mass production line. The ends of the tube ofthe terminal embracing the contact head of a spark plug must bemechanically interconnected and yet provide springiness for closeinterconnection while providing an inwardly projecting tab or detent tocooperate with the undercut in the contact head of the spark plug.

It is therefore a principal object of this invention to provide aterminal which is made from a single piece of material in connected formfor mass production which has a locked barrel and a tab or detentprojecting into the barrel to interlock with the contact head of a sparkplug.

Other objects and advantages of this invention relating to thearrangement, operation and function of the related elements of thestructure, to various details of construction, to combination of partsand to economics of manufacture will be apparent to those skilled in theart upon consideration of the following description and appended claims,reference being bad to the accompanying drawings forming a part of thisspecification wherein like reference characters designate correspondingparts in the several views.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an perspective, view of aconnected series of terminals as produced on a mass production line.

FIG. 2 is a plan view of the barrel portion of the terminal.

FIG. 3 is an elevational side view partly in section of the barrelportion and FIG. 4 is an elevational end view of the barrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings,particularly to FIG. 1, a flat ribbon of metal 10 which may be stored ina large reel (not shown) is fed into a stamping machine (not shown)wherein a progressive die stamps the metal ribbon in steps to form acomplete terminal T. The terminal T remains in attached condition to theribbon by tabs t so that it may again be stored on a reel for use inanother automatic machine for attachment to wire or wire harnesses whichare to be used in connection with the ignition system of an automotivevehicle. These stamping and forming steps on the metal ribbon 10 are oldin the art and will not be described in further detail. The completeterminal T includes a ferrule secinternal diameter to fit snugly overthe terminal head 7 SP of a spark plug as shown in FIG. 3 to makeelectrical connection therewith. The fit is such that the barrel isexpanded slightly against the springiness of the metal material whichhas ends 10 and 12 which overlap each other for about 30 degrees of areas best seen in FIG. 4. The inner end 12 is provided with a longitudinalrectangular aperture 14, the transverse dimension of which is at leasttwice 'as wide as the transverse dimension of a longitudinal arcuatetang 16 formed interiorly of the outer end 10, the parts being arrangedso that the tang 16 extends into the aperture 14 and projects into thebarrel B to contact the head SP of the spark plug to preventdisengagement as shown in FIG. 3.

The aperture 14 and the arcuate tang 16 are punched in the ribbon 10during the forming operation on the dies as shown in FIG. 1. Thereafter,in the final step of the forming process when the ends 10 and 12 of thebarrel position B are overlapped, the arcuate tang 16 is fitted into theaperture 14 so as to project into it at substantially a central locationso that end 10 lifts up with spring tension during the fitting on orremoval of the barrel B from the terminal head SP. The overlap of theends 10 and 12 of the barrel B may be controlled during manufacture by alongitudinal ridge X formed on the inner end 12 and contacted by the endface 10A of the outer end 10 to limit the overlap. There is a relaxationafter formation of the barrel, to allow the tang 16 to retreat to itscentral location in the aperture 14. The arcuate tang 16 contacts theterminal head SP behind its end enlargement. The engagementdisengagementforces may be varied by removing metal at the spring base such asproviding an aperture 17 ap' proximately in line with one edge ofsection C. The arcuate tang 16 when inserted into the aperture 14 actsas a lock to prevent excessive openings of the barrel during a severelyabusive removal of the terminal from a spark plug, such as commonlyencountered when service mechanics yank the spark plug wire from thespark plug at great angles to the axis of the spark plug.

It will be understood that the ribbon 10 may be provided with protectivemetal coats or plating such as cadmium or the like as is well known inthe art. When the terminal is to be applied to an ignition lead wire,the storage spool for the terminal tape is applied toan automaticmachine for this purpose, and the terminals are removed from the tapeone by one as used by breaking the connecting tab b between the terminalunits.

I claim:

1. A metallic connector for connecting the end of an ignition wire tothe rigid head of a spark plug comprising, in combination, a generallycylindrical barrel portion for releasable attachment to said spark plughead, an open ferrule portion for subsequent permanent attachment tosaid wire end and an intermediate arcuate center section integrallyconnecting said barrel and ferrule portions, said barrel portion beingformed of a single rounded section having its opposed lateral edgesoverlapping each other to provide a sector of said barrel of doublethickness, an aperture extending through the inner lateral overlappededge having a transverse width of less than the amount of overlap ofsaid edges, a tang extending radially inwardly from the outer lateraloverlapped edge of said barrel portion through said aperture andterminating within said barrel interior to provide a biased retainingmeans for engagement with said spark plug head, the lateral width ofsaid tang being less than said width of said aperture to permit relativemovement of said overlapping edges during engagement with said plug assaid barrel portion resiliently expands, an axially extending ridge onsaid barrel portion closely adjacent the outer lateral edge of saidoverlapped edges to define the maximum permissible overlap of saidlateral edges, said ferrule portion including a pair of open armsextending outwardly from a curved base and said intermediate arcuatecenter secportion.

1. A metallic connector for connecting the end of an ignition wire tothe rigid head of a spark plug comprising, in combination, a generallycylindrical barrel portion for releasable attachment to said spark plughead, an open ferrule portion for subsequent permanent attachment tosaid wire end and an intermediate arcuate center section integrallyconnecting said barrel and ferrule portions, said barrel portion beingformed of a single rounded section having its opposed lateral edgesoverlapping each other to provide a sector of said barrel of doublethickness, an aperture extending through the inner lateral overlappededge having a transverse width of less than the amount of overlap ofsaid edges, a tang extending radially inwardly from the outer lateraloverlapped edge of said barrel portion through said aperture andterminating within said barrel interior to provide a biased retainingmeans for engagement with said spark plug head, the lateral width ofsaid tang being less than said width of said aperture to permit relativemovement of said overlapping edges during engagement with said plug assaid barrel portion resiliently expands, an axially extending ridge onsaid barrel portion closely adjacent the outer lateral edge of saidoverlapped edges to define the maximum permissible overlap of saidlateral edges, said ferrule portion includIng a pair of open armsextending outwardly from a curved base and said intermediate arcuatecenter section connecting said barrel and ferrule portions havingsubstantially the same radius of curvature as said barrel portion andsaid curved base of said ferrule portion.
 2. The connector of claim 1wherein said barrel portion includes an elongate opening positionedsubstantially in alignment with a lateral edge of said intermediatecenter section to vary the resiliency of said barrel portion.